Apps Built for Hobbyists
SPQR Developers builds simple, powerful tools that help you get more joy from the hobbies you love —
from gardening to collectibles and beyond.
Our Apps
Smart, easy-to-use tools built with care
GrowZone+
Your personal planting companion. GrowZone helps you choose the right plants for your climate, sunlight, and soil — then keeps your garden notes and photos synced across all your devices.
Auction Calculator
A fast, accurate way to calculate true auction costs. Hammer price, buyer’s premium, shipping, taxes, currency conversion — all handled instantly.
Penfolio
A collector-focused app that catalogs, organizes, and values pen and ink collections — whether you’re a seasoned calligrapher or a new collector who appreciates fine pens, inks and writing.
Tempus Archive
A collector-focused app that catalogs, organizes, and reports on watch collections. Track your watches with precision. Log service history, straps, wear patterns and accuracy insights – all with iCloud sync.
Why SPQR Developers?
Thoughtfully crafted apps made with clarity and precision
Clean, intuitive designs
Built for accuracy and speed
Solves real hobbyist needs
Apps made with personal craftsmanship
Learn More
Interested in our apps or future projects?